1. Field of the Invention
The invention relates in general terms to ignition devices as are used for the ignition of a pyrotechnic passenger protection device. In particular, the invention relates to the configuration of the housing of an ignition device of this type.
2. Description of Related Art
In particular airbags and seatbelt tensioners are used as pyrotechnic passenger protection devices in motor vehicles. Safety systems of this type can considerably reduce the risk of injury. However, a precondition is that the safety systems must not fail in the event of a collision. In this context, particular attention is also paid in particular to the ignitors of pyrotechnic devices of this type, which are indispensable for a safety device of this type to function.
In particular, the ignitors have to continue to function perfectly even many years after they have been produced. To ensure that they function perfectly, it is necessary to ensure that the propellant charge which is present in the ignitor does not change over the course of time. Changes of this type may be caused, for example, by moisture penetrating into the ignitor. It is therefore important for the propellant charge of the ignitor to be hermetically encapsulated. The ignitor also has to release the gases from the ignited propellant charge in the correct direction in order to ignite the propellant charge of a gas generator of the safety system. To ensure that this occurs, ignitors which are known from the prior art have a cap or a cover and a similar solid base, between which the propellant charge is enclosed in a cavity formed from these parts. This design is intended to ensure that in any event the cap or the cover or part of it tears off.
Ignitors of this type are known for example from DE 203 07 603 01, DE 198 36 278 C2, DE 10 2004 005 085 A1, DE 101 16 785 A1, DE 198 36 278 A1 or DE 100 39 447 A1. Complex turned parts generally have to be used for the solid bases. A further problem with bases of this type is that of producing a hermetic connection to the cap or cover. At least during welding, the component is subject to considerable heating, since the solid base dissipates a large amount of heat from the welding location